Materials Explainer: 3D Printing in Frosted Ultra Detail (FUD)

For scale models, miniatures, and other 3D prints where fine details matter, Shapeways community members turn to Frosted Ultra Detail (FUD) plastic. FUD pieces have a surface quality and level of detail comparable to cast resin, and the additive manufacturing process allows designs to realize an unlimited array of ideas, many more than if they were using molds.

3D printing in FUD involves a process called Multijet Modeling, in which ultraviolet light is used to cure layer upon layer of liquid plastic. Once the final layer has set and the 3D printer stops, the translucent pieces are heated, washed to remove wax supports, inspected for quality, and hand-dried.

Frosted Extreme Detail (FXD), which has layers almost twice as fine as FUD, follows a similar process.

When designers can produce details on the scale of a human hair without the constraints of traditional casting processes, they can create amazing things.

“I always start with the smallest details, designing them at the minimum threshold, then bulking up the surrounding details so the piece stays in proportion,” Kacie Hultgren, who sells furniture for dollhouses and architectural models at her Shapeways shop Pretty Small Things, says.

To prepare for painting his pieces, Antonio Regidor, who sells miniature spaceships and other sci-fi models at 308 Bits, uses isopropyl alcohol or acetone — “But watch out!” he says. “These products can dissolve/melt FUD so the parts must have a short bath —seconds — and rinse with water immediately.“ Then he sands them before painting.

A painted scale model from Lenni’s Modelshop

Kacie prefers dish soap and warm water to prepare for painting. “If there is excess wax left on the piece, I put them on a sunny window sill with a paper towel underneath to catch the melted wax,” she says. She prefers Testors acrylic model paints.

Plenty of FUD pieces remain unfinished. Their delicate beauty, however, can be challenging to capture in a photograph. Here’s Kacie’s approach:

I like to use a dark, rich colored background. Then I try to set up the best lighting situation I can. Sometimes I’ve used a low cost LED ring light over the lens of my camera or phone. Other times I can get away with ambient light. Most importantly, I shine a flashlight from the top. Flashlights with adjustable intensity work best. I often use parchment or tissue paper over the lens to diffuse the light. The light from above highlights the details in the FUD that can otherwise get lost in a photo and brightens the material so it’s clearly distinguished from the background.

What have you made in FUD? Share your projects in the comments below for a chance to be featured on the blog.

3 comments

I have to disagree with the statement that “FUD pieces have a surface quality and level of detail comparable to cast resin”. Even FXD requires an extreme amount of time for sanding to get a smooth surface close to cast resin. And in most cases it comes with the cost of sanding away details, for which I chose FUD or FXD in the first place. As long as 3D printing hasn’t evolved enough to overcome this issue, best would be to have a basic 3D model without details. This facilitates the sanding process and the details can be added later on. Either printed separately or obtained through other processes like photo etching and in some cases even details already available in the mainstream market.

I have to agree with Dennis above. We cast parts daily at 3DSI and there is no evidence of visible lines and in some cases we cast optically clear. There’s not a printing technology available today that can produce the level of detail that we cast.